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Thread: Laying out PCB traces the old way

  1. #11
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    Interesting. Man that sounds like a chore. It makes me respect people like Lee who were doing it as a profession even more.

    On the subject of CAD... supposedly the Nascom-1 was one of the first home machines designed that way. But I read the process was wonky and caused the design to come out much more complicated than it otherwise would have been. I wonder how the process would have caused that. It was a relatively new Irish firm apparently contracted to do the actual design.

  2. #12
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    I think the big iron vendors were the first to make use of CAD for PCB layout--i.e. IBM, CDC, DEC...

    But recall that back in the "good old days", program development wasn't much better. You wrote your code out on a keypunch form and turned it into the keypunch pool, listed your deck on a 407 and compared it against your handwritten listing for accuracy. (I'll never forget the time that I got my deck back from keypunch with a note saying "I wasn't able to tell if your was zero or the letter, so I did some of both". This, in spite of the notation on the coding form. Deck->trash and repeat with a note writ large.) Submit deck, wait for output, correct errors, lather, rinse repeat. Back then, I read somewhere that the average output of a coder was 13 lines of debugged code per day. That's probably not accurate, but likely not far from the truth.

    Terminals? Only the very senior people had access to them. OTOH, block time was easy to get, so you could use your $500/hour system as a keypunch...

  3. #13
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    Semiconductors were initially very simple designs and people just kept making them larger is complexity and smaller in size. Lots of people were required to learn methods of design and layout that are now done by CAD with the old manual designing methods forgotten. Hundreds of people were needed to do what one person can do today. The downside to this is the complexity makes churning out one chip expensive but millions of chips cheap.
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  4. #14

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    I have found over the years the trick to good pcb's is simply to draw them in a drawing program and that with practice the track layout can be better than a computer auto-routed design based on schematic capture. It just takes longer.

    I have no pcb dedicated software, but found I could draw an image as a .png file of what I wanted and I could make the pcb myself with iron on film (printed in a laser printer) and ferric chloride etch. But for double layer boards with plated through holes, unless simple, I just send the diagram to a pcb maker and they have software that converts it into an Altium file.

    To draw it I use the transparency function and lay it out over a 2.54mm grid and can separate the layers. The drawing program I use it Microsoft's Picture IT (vintage about 2004) photo edit software. The results can be good. Have a look at the pcb in this article done this way that has over 66 IC's , scroll through the article to see the various photos/diagrams:

    http://worldphaco.com/uploads/ARCADE_MINI-PONG.pdf

    I often wonder how the old pcb's were made/designed, I know the one for Arcade Pong (1972), was hand drawn at the time. Some pcb designs are definitely eye catching. One that impresses me a lot is the IBM CGA video card. The track arrangements have a look that they were most likely computer designed (routed), but I might be wrong, but they are really very good looking tracks.

  5. #15
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    By the time the IBM PC came out, IBM was using CAD for its layout.

    For a lot of my designs, I'm happy if the autorouter gets the job done after power traces have been laid out. I don't have the time to sweat doing the whole thing manually and the speeds I work at make layout less critical.

    Use a decent EDA package and you wind up with a nice-looking schematic, gerber, drill and silkscreen files without enormous amounts of work.

  6. #16
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    My favorite layout is still the compumotor board I have; on the component side there are a few Egyptian symbols and genuine hieroglyphics. I posted a pic at the end of a post in another thread: http://www.vcfed.org/forum/showthrea...517#post468517

    Yeah, likely done by hand, with routing around the Eye of Horus and the figures of Osiris and Hathor.
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